Lesson blocks, marking marathons, parents' evenings — schedule math in the language of the timetable.
A teaching day is a chain of fixed-length blocks — lessons, breaks, duties, marking — and planning it means adding durations to clock times over and over. TCalc does exactly that: type the plan as an expression and read off the answer.
It also settles the honest questions: how much of the week do six 45-minute lessons actually take?
Six lessons of teaching time.
When does this period end?
Eight parent meetings at 15 minutes each.
Need marking done by noon? That's your start time.
Multiply the lesson length by the count: 45m × 6 = 4h 30m per day, and chain days together for the week. TCalc keeps the minutes exact.
Yes — subtract the duration from the deadline: 12:00 − 90m = 10:30 AM is when you need to start.
Yes — the calculator is free with no sign-up, works in any browser, and there's an Android app. A free account adds cloud-synced history.